/*	Copyright 2001, 2002 Georges Menie (www.menie.org)    This program is free software; you can redistribute it and/or modify    it under the terms of the GNU Lesser General Public License as published by    the Free Software Foundation; either version 2 of the License, or    (at your option) any later version.    This program is distributed in the hope that it will be useful,    but WITHOUT ANY WARRANTY; without even the implied warranty of    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the    GNU Lesser General Public License for more details.    You should have received a copy of the GNU Lesser General Public License    along with this program; if not, write to the Free Software    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA*/#include "baselib.h"#include "xmodem.h"#include "crc16.h"#include "xmodemdefs.h"int xmodemTransmit(unsigned char *src, int srcsz){	unsigned char xbuff[1030]; /* 1024 for XModem 1k + 3 head chars + 2 crc + nul */	int bufsz, crc = -1;	unsigned char packetno = 1;	int i, c, len = 0;	int retry;	for(;;) {		for( retry = 0; retry < 16; ++retry) {			if ((c = _inbyte((DLY_1S)<<1)) >= 0) {				switch (c) {				case 'C':					crc = 1;					goto start_trans;				case NAK:					crc = 0;					goto start_trans;				case CAN:					if ((c = _inbyte(DLY_1S)) == CAN) {						_outbyte(ACK);						FLUSHINPUT;						return -1; /* canceled by remote */					}					break;				default:					break;				}			}		}		_outbyte(CAN);		_outbyte(CAN);		_outbyte(CAN);		FLUSHINPUT;		return -2; /* no sync */		for(;;) {		start_trans:			xbuff[0] = SOH; bufsz = 128;			xbuff[1] = packetno;			xbuff[2] = ~packetno;			c = srcsz - len;			if (c > bufsz) c = bufsz;			if (c >= 0) {				memset (&xbuff[3], 0, bufsz);				if (c == 0) {					xbuff[3] = CTRLZ;				}				else {					memcpy (&xbuff[3], &src[len], c);					if (c < bufsz) xbuff[3+c] = CTRLZ;				}				if (crc) {					unsigned short ccrc = crc16_ccitt(&xbuff[3], bufsz);					xbuff[bufsz+3] = (ccrc>>8) & 0xFF;					xbuff[bufsz+4] = ccrc & 0xFF;				}				else {					unsigned char ccks = 0;					for (i = 3; i < bufsz+3; ++i) {						ccks += xbuff[i];					}					xbuff[bufsz+3] = ccks;				}				for (retry = 0; retry < MAXRETRANS; ++retry) {					for (i = 0; i < bufsz+4+(crc?1:0); ++i) {						_outbyte(xbuff[i]);					}					if ((c = _inbyte(DLY_1S)) >= 0 ) {						switch (c) {						case ACK:							++packetno;							len += bufsz;							goto start_trans;						case CAN:							if ((c = _inbyte(DLY_1S)) == CAN) {								_outbyte(ACK);								FLUSHINPUT;								return -1; /* canceled by remote */							}							break;						case NAK:						default:							break;						}					}				}				_outbyte(CAN);				_outbyte(CAN);				_outbyte(CAN);				FLUSHINPUT;				return -4; /* xmit error */			}			else {				for (retry = 0; retry < 10; ++retry) {					_outbyte(EOT);					if ((c = _inbyte((DLY_1S)<<1)) == ACK) break;				}				FLUSHINPUT;				return (c == ACK)?len:-5;			}		}	}}